1. Field of Invention
The invention relates to brain wave medical systems and methods and more particularly to an electroencephalograph (EEG) system and method having improved spatial resolution.
2. Related Art
It is presently known that the brain waves of a human subject, at the microvolt level, may be amplified and analyzed using electroencephalograph (EEG) equipment. Generally 19 electrodes are electrically connected to the scalp of the subject and the brain waves are amplified and displayed in analog form. The U.S. Pat. No. 4,736,751, incorporated by reference, describes a system using a larger number of electrodes and various digital computer based methods to obtain more information from the brain wave signals.
However, when many electrodes are used, for example, 256 electrodes, it is time consuming to obtain their location on the subject's scalp using the conventional technique of tape measurements. If the subject is a child, senile or infirm, the subject may not be able to hold still for the 15-30 minutes which may be required for such measurements. The physical location of the electrodes is required to compare the EEG recordings, at each electrode, with the information obtainable concerning the head of the subject from other medical image systems, such as MRI (Magnetic Resonance Imaging).
The information produced from the EEG recordings may be made more clear and meaningful when the brain wave data is enhanced and analyzed by various methods executed in a digital computer system. However, the presently available methods do not provide sufficient spatial resolution for some purposes.